A liquid crystal image-preserving tunable filter (IPTF) for cell microscopy is proposed. Recent developments in birefringent liquid crystal technology should make it possible to construct an inexpensive (<$10,000), large- aperture, tunable filter than ranges from 400 to 800 nm in less than a millisecond with no moving parts and a 10 to 20 nm bandwidth. There are numerous optical probing techniques for studying the dynamics, the chemical processes and the membrane transport mechanisms of living cells. Their efficacy depends strongly on ability to detect shifts in excitation, emission or absorption spectra by monitoring narrow bandwidths of light. As more probing techniques are developed and systems become more complicated, automation,versatility, speed, and convenience will be increasingly important. An IPTF liquid crystal IPTF would advance the art in many of these areas. During Phase I, we evaluated several individual liquid crystal elements and two assembled filters. During Phase II, we propose to design and build prototypes for fluorescence microscope imaging systems, characterize them thoroughly, and test them at field sites. Field tests will compare the performance of the IPTF to conventional techniques of filtering and explore the practical aspects of incorporating the IPTF into fluorescence microscope imaging systems.